<html>
<head>
	<meta charset="UTF-8">
	<meta content="IE=edge" http-equiv="X-UA-Compatible">
	<meta content="initial-scale=1.0, maximum-scale=1.0, user-scalable=no, width=device-width" name="viewport">
	<title>2300：[HAOI2011]防线修建</title>
	<!-- css -->
	<link href="../css/base.min.css" rel="stylesheet">
	<link href="../css/project.min.css" rel="stylesheet">
	
	<!-- favicon -->
	<!-- ... -->
</head>
<body class="page-brand">
	<header class="header header-transparent header-waterfall ui-header">
		<ul class="nav nav-list pull-left">
			<li>
				<a data-toggle="menu" href="#menu">
					<span class="icon icon-lg">menu</span>
				</a>
			</li>
		</ul>
		<a class="header-logo header-affix-hide margin-left-no margin-right-no" data-offset-top="213" data-spy="affix">[HAOI2011]防线修建</a>
		<span class="header-logo header-affix margin-left-no margin-right-no" data-offset-top="213" data-spy="affix">[HAOI2011]防线修建</span>
	</header>
	<nav aria-hidden="true" class="menu" id="menu" tabindex="-1">
		<div class="menu-scroll">
			<div class="menu-content">
				<a class="menu-logo" href="../index.html">BZOJ离线题库</a>
				<ul class="nav">
					<li>
						<a class="waves-attach" data-toggle="collapse" href="#problems">题目</a>
						<ul class="menu-collapse collapse in" id="problems">
							<li>
								<a class="waves-attach" href="../index.html">主页</a>
							</li>
							<li>
								<a class="waves-attach" href="../list.html">题目列表</a>
							</li>
						</ul>
					</li>
					<li>
						<a class="collapsed waves-attach" data-toggle="collapse" href="#about">关于</a>
						<ul class="menu-collapse collapse" id="about">
							<li>
								<a class="waves-attach" href="../about.html">关于此项目</a>
							</li>
						</ul>
					</li>
					
				</ul>
			</div>
		</div>
	</nav>
	<main class="content">
		<div class="content-header ui-content-header">
			<div class="container">
				<h1 class="content-heading">
                [HAOI2011]防线修建                </h1>
                <p>时间限制：10s&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  空间限制：512MB</p>			</div>
		</div>
		<div class="container">
			<section class="content-inner margin-top-no">
				<div class="row">
					<div class="col-lg-13 col-md-13">
						<div class="card margin-bottom-no">
							<div class="card-main">
								<div class="card-inner">
									
                                <h3>题目描述</h3><p><p><!--[if !mso]>
<style>
v\:* {behavior:url(#default#VML);}
o\:* {behavior:url(#default#VML);}
w\:* {behavior:url(#default#VML);}
.shape {behavior:url(#default#VML);}
</style>
<![endif]--><!--[if gte mso 9]><xml>
<w:WordDocument>
<w:View>Normal</w:View>
<w:Zoom>0</w:Zoom>
<w:PunctuationKerning />
<w:DrawingGridVerticalSpacing>7.8 磅</w:DrawingGridVerticalSpacing>
<w:DisplayHorizontalDrawingGridEvery>0</w:DisplayHorizontalDrawingGridEvery>
<w:DisplayVerticalDrawingGridEvery>2</w:DisplayVerticalDrawingGridEvery>
<w:ValidateAgainstSchemas />
<w:SaveIfXMLInvalid>false</w:SaveIfXMLInvalid>
<w:IgnoreMixedContent>false</w:IgnoreMixedContent>
<w:AlwaysShowPlaceholderText>false</w:AlwaysShowPlaceholderText>
<w:Compatibility>
<w:SpaceForUL />
<w:BalanceSingleByteDoubleByteWidth />
<w:DoNotLeaveBackslashAlone />
<w:ULTrailSpace />
<w:DoNotExpandShiftReturn />
<w:AdjustLineHeightInTable />
<w:BreakWrappedTables />
<w:SnapToGridInCell />
<w:WrapTextWithPunct />
<w:UseAsianBreakRules />
<w:DontGrowAutofit />
<w:UseFELayout />
</w:Compatibility>
<w:BrowserLevel>MicrosoftInternetExplorer4</w:BrowserLevel>
</w:WordDocument>
</xml><![endif]--><!--[if gte mso 9]><xml>
<w:LatentStyles DefLockedState="false" LatentStyleCount="156">
</w:LatentStyles>
</xml><![endif]--><!--[if !mso]><object
classid="clsid:38481807-CA0E-42D2-BF39-B33AF135CC4D" id=ieooui></object>
<style>
st1\:*{behavior:url(#ieooui) }
</style>
<![endif]--><!--[if gte mso 10]>
<style>
/* Style Definitions */
table.MsoNormalTable
{mso-style-name:普通表格;
mso-tstyle-rowband-size:0;
mso-tstyle-colband-size:0;
mso-style-noshow:yes;
mso-style-parent:"";
mso-padding-alt:0cm 5.4pt 0cm 5.4pt;
mso-para-margin:0cm;
mso-para-margin-bottom:.0001pt;
mso-pagination:widow-orphan;
font-size:10.0pt;
font-family:"Times New Roman";
mso-ansi-language:#0400;
mso-fareast-language:#0400;
mso-bidi-language:#0400;}
</style>
<![endif]--></p>
<div>近来A国和B国的矛盾激化，为了预防不测，A国准备修建一条长长的防线，当然修建防线的话，肯定要把需要保护的城市修在防线内部了。可是A国上层现在还犹豫不决，到底该把哪些城市作为保护对象呢？又由于A国的经费有限，所以希望你能帮忙完成如下的一个任务：</div>
<div>1.给出你所有的A国城市坐标</div>
<div>2.A国上层经过讨论，考虑到经济问题，决定取消对i城市的保护，也就是说i城市不需要在防线内了</div>
<div>3.A国上层询问对于剩下要保护的城市，修建防线的总经费最少是多少</div>
<div>你需要对每次询问作出回答。注意单位1长度的防线花费为1。</div>
<div>A国的地形是这样的，形如下图，x轴是一条河流，相当于一条天然防线，不需要你再修建</div>
<div>A国总是有两个城市在河边，一个点是(0,0)，一个点是(n,0)，其余所有点的横坐标均大于0小于n，纵坐标均大于0。A国有一个不在(0,0)和(n,0)的首都。(0,0),(n,0)和首都这三个城市是一定需要保护的。</div>
<p class="MsoNormal"><span style="font-size: 12pt; font-family: 宋体;"><img height="255" width="307" src="../file/2300_0.jpg" alt="" /></span></p>
<p class="MsoNormal" style="text-align: left;">上图中，A,B,C,D,E点为A国城市，且目前都要保护，那么修建的防线就会是A-B-C-D，花费也就是线段AB的长度+线段BC的长度+线段CD的长度,如果，这个时候撤销B点的保护，那么防线变成下图</p>
<p class="MsoNormal" style="text-indent: 24pt;"></p>
<p class="MsoNormal" style="text-indent: 24pt;"><span style="font-size: 12pt; font-family: 宋体;"><img height="271" width="325" src="../file/2300_1.jpg" alt="" /></span></p>
<p align="center" class="MsoNormal" style="text-align: center; text-indent: 24pt;"><span lang="EN-US" style="font-size: 12pt;"><br />
</span></p></p><hr/><h3>输入格式</h3><p><div>第一行，三个整数n,x,y分别表示河边城市和首都是(0,0)，(n,0)，(x,y)。</div>
<div>第二行，一个整数m。</div>
<div>接下来m行，每行两个整数a,b表示A国的一个非首都非河边城市的坐标为(a,b)。</div>
<div>再接下来一个整数q，表示修改和询问总数。</div>
<div>接下来q行每行要么形如1 i，要么形如2，分别表示撤销第i个城市的保护和询问。</div>
<p></p></p><hr/><h3>输出格式</h3><p><p><span style="font-size: 12pt; font-family: 宋体;">对于每个询问输出</span><span lang="EN-US" style="font-size: 12pt;">1</span><span style="font-size: 12pt; font-family: 宋体;">行，一个实数</span><span lang="EN-US" style="font-size: 12pt;">v</span><span style="font-size: 12pt; font-family: 宋体;">，表示修建防线的花费，保留两位小数</span></p></p><hr/><h3>样例输入</h3><pre>4 2 1                                
2                                  
1 2                               
3 2                               
5                                 
2
1 1
2
1 2
2</pre><hr/><h3>样例输出</h3><pre>6.47
5.84
4.47</pre><hr/><h3>提示</h3><p><div>m&lt;=100000,q&lt;=200000,n&gt;1</div>
<div>所有点的坐标范围均在10000以内, 数据保证没有重点</div></p><hr/><h3>题目来源</h3><p>没有写明来源</p>
								</div>
							</div>
						</div>
					</div>
				</div>
				
				
			</section>
		</div>
	</main>

	<div class="fbtn-container">
		<div class="fbtn-inner">
			<a class="fbtn fbtn-lg fbtn-brand-accent waves-attach waves-circle waves-light waves-effect" data-toggle="dropdown" aria-expanded="true"><span class="fbtn-text fbtn-text-left">Menu</span><span class="fbtn-ori icon">apps</span><span class="fbtn-sub icon">close</span></a>
			<div class="fbtn-dropup">
				<a class="fbtn fbtn-brand waves-attach waves-circle waves-light waves-effect" href="../list.html" target="_self"><span class="fbtn-text fbtn-text-left">题目列表</span><span class="icon">menu</span></a>
				<a class="fbtn fbtn-green waves-attach waves-circle waves-effect" href="../index.html" target="_self"><span class="fbtn-text fbtn-text-left">返回主页</span><span class="icon">home</span></a>
				<a class="fbtn waves-attach waves-circle waves-effect" href="http://www.lydsy.com/JudgeOnline/submitpage.php?id=2300" target="_blank"><span class="fbtn-text fbtn-text-left">提交代码</span><span class="icon">send</span></a>
				<a class="fbtn fbtn-orange waves-attach waves-circle waves-effect" href="http://www.lydsy.com/JudgeOnline/wttl/wttl.php?pid=2300" target="_blank"><span class="fbtn-text fbtn-text-left">试题讨论</span><span class="icon">chat</span></a>
				
			</div>
		</div>
	</div>

	<!-- js -->
	<script src="../js/jquery.min.js"></script>
	<script src="../js/base.min.js"></script>
	<script src="../js/project.min.js"></script>
</body>
</html>